Rotary pump or motor



Oct. 22, 1963 A. l. MIHALKls ROTARY PUMP OR MOTOR Filed oct. 10. 196;

6 Sheets-Sheet 1 0d. 22, 1963 A. 1. MIHALAKls 3,107,846 v ROTARY lPUMP OR MOTOR 6 sheets-sheet 2 Filed Oct. l0. 1961 IN VEN TOR.

Oct. 22, 1963 A. l. MIHALAKIS ROTARY PUMP OR MOTOR 6 Sheets-Sheet 3 Filed Oct. l0, 1961 WM/m UCL 22,' 1953 v v A. l. MIHALAKls 3,107,846

` ROTARY PUMP OR MOTOR Filed Oct. 10. 1961 6 Sheets-Sheet 4 @67S M/HQZK/S INVENTOR.

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Oct. 22, 1963 A. A'1. MIHALAkls 3,107,846

Romy PUMP oR` MoToR I Filed oct. 10.'.1961 e sheets-sneer e BY A United States Patent O 3,107,846 ROTARY PUMP R MOTOR Agis I. Mhalakis, Northridge, Calif., assignor, lby mesne assignments, to Aim Pump Corporation, Canoga Park, Calif., a corporation of California Filed Oct. 10, 1961, Ser. No. 144,135 27 Claims. (Cl. 23d- 149) This invention relates to the art of rotary uid pumps and rotary fluid motors and is particularly directed to an improved form of rotary compressor for compressing alr or other gases. This application constitutes a continuation-in-part of my co-pending application, Serial No. 707,442, led January 6, 1958, now abandoned, and 1s concerned with the type of rotary device having a cylindrical impeller mounted eccentrically to turn within a cylindrical chamber in a housing and having a reciprocating blade guided on the housing and contacting the impeller.

It is an object of the present invention to provide a rotary pump or motor of this type having exceptionally high eciency and capable of prolonged or continuous service without overheating. Another object is to provide such a device of relatively low weight and small size. Other objects `are -to provide such a device having improved seal means for the ends of the impeller within the chamber, improved sliding seals for the blade faces, and improved means for controlling the action of the reciprocating blade, including a motion-reversing apparatus which contacts the blade at Ithe extreme end of its outward stroke to apply a force to the blade to reverse its direction of travel. Another object is to provide a rotary compressor of this type having a closed cavity for receiving each reciprocating blade, together with means for providing tluid pressure of regulated intensity in each blade cavity, to assist in main-taining the blade in sliding contact with the surface of the rotating impeller. Another object is to provide a construction wherever the parts of the stationary housing may be initially aligned and centered with respect to the rot-ary shaft. A related object -is to provide an improved form of wiper bar assembly for the rotary eccentric impeller. Another object is to provide a device which includes means whereby it may readily be assembled with any desired number of stages, by stacking of standard component p-arts. A still further object is to provide an improved lubrication system for the internal working parts of the device.

Other and more detailed objects and advantages will appear hereinafter.

In the drawings:

FIGURE 1 is a longitudinal sectional view showing a preferred embodiment of this invention.

FIGURE 2 is a transverse sectional View taken substantially on lines 2-2 as shown in FIGURE 1.

FIGURE 3 is a sectional View showing 'a portion of the device of FIGURE 2 on an enlarged scale, the moving parts being shown in a different position.

FIGURE 4 is an enlarged sectional detail showing a portion of the device of FIGURE 3.

FIGURE 5 is a sectional detail taken substantially on the lines 5 5 `as shown in FIGURE 2.

FIGURE 6 is a sectional detail taken substantially on lines 6-5 as shown on FIGURE 1.

FIGURE 7 is a schematic drawing showing the lluid ow connections between the two stages of the rotary compressor and the storage tank.

FIGURE 8 is an end view of the divider Wall.

FIGURE 9 is a perspective view of one of the reciprocating blades.

FIGURE 10 is a view taken in the direction |of the lines 10--10 as shown in FIGURE 2.

3,137,846 Patented Get. 22,1963

FIGURE 1l is a longitudinal sectional view showing a modiiication.

FIGURE l2 is an end elevation of a portion of a device shown in FIGURE 11.

FIGURE 13 is a sectional detail of a portion of FIG- URE 12, shown yon an enlarged scale, the parts being in a different position.

Referring to the drawings:

The rotary compressor generally designated 10 may be single stage or multiple stage device, and the particular device illustrated has two stages. The housing generally designated 11 is formed of individual segments 12 and 13 separated by `a divider wall 14 Aand connected to closure heads 15 and 16 by axially extending tension bolts 9. One housing segment is provided for each of the stages of compression. A rotary shaft 17 extends through the parts 'of the housing 11 and is mounted to turn on bearings 18 and 19 supported on the closure lheads 15 and 16. If desired -a third bearing may be mounted on the divider wall 14. A shaft seal 20 is provided on the closure head 15 adjacent the bearing 18.

A cylindrical impeller 21 is xed eccentrici'ally lon the shaft 17 within the housing segment 12 ,and similarly the cylindrical impeller 22 is iixed -eccentrically on the shaft 17 within the housing segment 13. The impellers 21 and 22 are shown spaced angularly approximately one-half revolution apart. A radially reciprocating blade 23 contacts the `outer cylindrical surface 24 of the impeller 21, and a similar blade 25 contacts the outer cylindrical surface of the impeller 22.

The reciprocating blade 23 is mounted to slide radially within parallel guide grooves 26' and 27 provided in the closure head 15 and divider wall 14, land the blade 25 slides within guide grooves 2S and 29 in the divider wall 14 Iand closure head 16. The blades are preferably formed of steel and the parts 15 and 14 and 16 may be formed of alloy iron to afford optimum sliding contact with the steel blades. The impellers 21 and 22 are fixed to the shaft 17 by means of keys 29 and set screws 30. Since the blade, impeller and associated parts are lthe same, except for Size, in each of the stages of the rotary compress-or, only one set need be described in detail.

The housing segment 12 is provided with an inner cylindrical wall 32 defining a chamber 33 which receives the eccentric impeller 21. The cylindrical Wall 32 is con-Ky centric with the axis of the shaft 17. The housing segment 12 is also provided with walls forming a pressure cavity 34 and a slot 35 connecting the pressure cavity 34 to the cylindrical chamber 33. The reciprocating blade 23 extends through the slot 35 and into the chamber 33 and into the pressure cavity 34.

The impeller 21 is provided with a wiper bar assembly 36 which includes a Wiper bar 37 having contact with the inner cylindrical surface 32 of the housing segment 12. This bar element 37 is mounted within an axially extending recess 38 provided on the impeller 21 at a location most remote `from the shaft axis. A leaf spring 39 is mounted Within the recess and acts to hold the bar element 37 is sliding contact with the cylindrical surface 32. The leaf spring 39 is about one-half the length of wiper bar 37 and contacts the Wiper bar at the extreme ends of the leaf spring. The wiper bar 37 is thus symmetrically loaded at its one-quarter length points by means of the' leaf spring 39. A rubber strip 40 and a metal strip 41 are mounted on the leading edge of the wiper bar 37 and within the recess 38. The resilience of the rubber strip provides the proper sliding fit between the wiper bar 37 and the sides of the recess 38 within which it is mounted. The metal strip 41 serves as a cover shield for the rubber strip 40 and is engaged by one end 42 of each split seal ring 43 positioned on each end face 44 of the impeller 21. The friction drag of each split seal ring.

arcas/.ie

43 against the adjacent end wall 44, 45 of the chamber 33 causes the ring end 42 to engage the metal strip 41 to maintain a seal on the high pressure side of the wiper bar assembly 36. The metal seal rings 43 are concentric with the cylindrical surface 24 of the impeller and these split rings are preferably tapered on their outer surfaces so as to expand resiliently along the daring surfaces 47 into endwise engagement with the end walls 45 and 46 of the chamber 33. The wiper bar 37 extends radially inward beyond the ends of the split seal rings 43.

The blade 23 is provided with a contact shoe or rail 48 at its leading edge. This rail may be formed of bronze and attached to the blade by any suitable means such as, for example, by brazing or riveting. The edge surface 49 of the rail 4S forms -a sealing contact with the cylindrical periphery 24 oi the impeller 21. Lips 50 on the rail 44 engage the side faces of the blade 23 and clearance spaces are provided at the entrance 51`to the slot 35 to permit these lips to .pass toward the pressure chamber 34. The impeller 21 is provided with axially extending internal openings 52 which reduce the off-center weight and `which establish communication between the end walls 45 and 46 of the chamber 33 within the split seal rings 43. These end Walls are defined by the plane surfaces of the parts 15 and 14.

A cylindrical bore 53 -is provided in the housing segment 12 and extends parallel to `the shaft axis. This bore intersects the slot 35, and extends for the full distance between the end walls 45 and 46. Sealing plugs or strips 54 and 55 are loosely mounted in the bore 53 and extend for the full length thereof. These sealing plugs are duplicates and each includes au arcuate portion 56 shaped to contact the Wall of the bore 53, a fiat portion 57 for surface contact with one face of the blade 23, and a heel surface S. The surfaces 56 and 517 intersect to provide a pointed end 59 for each plug. Each of the sealing strips 54 and 55 is provided with a longitudinal groove receiving a length of resilient rubber 60, -or other bias means such as, for example, a leaf spring. Each of these rubber strips 6d resiliently contacts the ywall of the cylindrical bore 53', but they need not extend for the full length thereof. Both of the plugs or sealing strips 5d and 55 reciprocate with the reciprocating blade 23, although the extent of their reciprocating movement is slight. When the blade 23 moves radially away from the shaft 17 both of the plugs 54 and 55 move in the same direction. The high pressure plug 54 forms a sealing Contact with the bore 53 in the arcuate region 61 wh'ile the low pressure plug 55 dorms a sealing contact with the bore 53 in the arcuate region 62. The relatively large effective area of the heel surface 5S of the plug 54 insures rapid action to set the plug 54 against the region 6l against the pressure Within the cavity 34. Similarly, the relatively large effective area of the heel surface 58 of the low pressure plug 55 insures rapid action to set the plug 55 against the region 62 against the pressure within the chamber 33. Visual inspection in test machines and examination of parts after disassembly shows that the plugs or sealing strips 54 and 55 each reciprocates between sealing regions 61 and 63 and sealing regions 62 and 64, respectively. The rubber strips 60 serve to urge the plugs 54 and 55 into initial slidingV contact with the blade 23 under start-up conditions, and to maintain flat surface contact with the blade at all times.

When the blade 23 moves into the pressure cavity 34 it increases the fluid pressure therein in accordance with its displacement and this tluid pressure exerts a force tending to maintain the blade in contact with the impeller 21. When the lblade reaches the retracted posit-ion shown in FIGURE 3 the rail 43 moves out of contact with the impeller momentarily and does not reverse its direction of motion to re-establish contact with the impeller surface 24 until it strikes the motion-reversing device generally designated 65. This device is show-n schematically and includes a plunger 66 mounted for radial movement within the body 67. The body 67 is secured and sealed to the housing segment 12, and is provided with a bore 68 which slidably receives an enlargement 69 provided on the plunger 65. A seal ring 70- prevents leakage between the plunger and the body 67. Belleville washers 71 provide a stop to limit inward travel of the plunger 66 under inuence of the relatively light compression spring 72. 'Ihis spring 72 engages the enlargement 69 at one end and engages the adjustment capy 73 at the other end. This cap is connected to the body 67 by moans of threads 74. If desired, one end of the plunger 66 may project through a central opening 75 Vin the adjustment cap 73. The force of the spring 72 is adjusted by turning the cap 73 with respect to the body 67.

The position of the lower end 71 of the plunger 66 is such that clearance exists between the blade 23 and the plunger 66 at all times when the shaft 17 and impeller 2l are turned slowly. However, when the shaft is turned at normal speed the blade 23 moves out of contact with the impeller surface 24 momentarily, because of its momentum allowing the wiper bar 37 to pass the blade 23 without contacting it. This overtravel of the blade 23 causes it to strike the end 76 ofV the plunger 66 and the force of the spring 72 reverses the direction of travel of the blade 23 and causes it to reengage the cylindrical surface 24 of the impeller 21. The force of the spring72 may be adjusted by means or" the threaded cap 73 to return the blade 23 into contact with the impeller surface at a point closely adjacent the position .of the wiper bar assembly 36.

lt will be observed from a consideration of FIGURE 3 4that a substantial portion of the end area of Jthe rail 48 is exposed to high pressure fluid developed in the chamber 33 on the high pressure side of the blade 23 when the wiper bar assembly 36 approaches the position of the rail 43. The low pressure side of the blade 23 acts over only a very small part of this end area of thev rail 43. The result is that increased pressure is applied endwise to the blade 23 to move it away from the impeller 2l and into the pressure chamber 34. Once the sliding contact between the rai-l 48 and cylindrical surface 24 of the impeller 21 has been interrupted, a sharp blast of duid passes from the high pressure side to the low pressure side of the blade 23. The Venturi effect of this` rapidly moving liuid stream reduces the lluid pressure between the surfaces 49 and 24 so that the .pressure in the cavity 34 acting on the blade 23, supplemented by the action lof the motion-reversing device 65, quickly returns the blade rail 48 into contact with the impeller surface 24.

The exposed end 77 =of the plunger 66 is accessible so' Experience has shown that after a period of operation v uid pressure will be built up in the cavity 34 by leakage through the slot 35 from the chamber 33. The pressure in the cavity 34 does not reach the maximum pressure developed in the chamber 33, however, because someH fluid under pressure leaks from the cavity 34 cyclically past the sealing plugs into the low pressure portion of the chamber. Accordingly, in normal operation the pres` sure'in the cavity 34 develops to an intensity somewhat greater than half the difference in pressure between the high pressure and low pressure sides of the blade 23. In `order to supplement the endwise force appliedby this fluid pressure in the cavity 34 to the blade 23, a pressure inlet '7S to the cavity 34 is provided on lthev housing segment l2. ln this way any `desired pressure up to the full intensity 4of pressure developed by the compressor lil may be applied to each ofthe pressure cavities through pressure regulators '79. This fluid pressure is preferably obtained by way of lines 8u communicating with the output conduit 81 leading to the tank 82.

Bumpers, not shown, may be mounted on each housing segment within its pressure cavity and adapted to be contacted by the reciprocating blade in the event of overtravel beyond the position of normal reversal, to prevent damage.

The drive pulley 83 is iixed to an youter projecting end 84 of the rotary shaft 17 and may be driven in any desirable manner from a source of power, not shown. The pulley may be counterweighted to balance the off-center load of the impellers 21 and 22. In a single stage compressor, this off-center load may be considerable, although the effect of the 'air pressure built up within the machine while running tends to reduce the vibration caused by olf-center loading. A fan 85 may be fixed to the pulley to cause a flow of air over the finned exterior of the rotary compressor to facilitate cooling. In operation, turning of the rotary shaft 17 causes the eccentric impellers 21 and 22 to turn within their respective chambers. Fluid, for example, air, passes inward through the air cleaner 86 and inlet passage 87 into the low pressure side of the chamber 33. As the shaft 17 and impeller rotate in the direction of the arrow, shown in FIGURE 2, the space within the chamber 33 `on the high pressure side of the blade 23 becomes smaller while the space on the low pressure side becomes greater. Air is thus drawn inward through the intake 87 through elliptical holes 88 in the curved bridge 89 and expelled through discharge passage 9i?, and similar holes in curved bridge 91. Discharged air then passes through check valve assembly 92 and conduit 93. The check valve assembly 92 is preferably of the type shown in my copending application Serial No. 84,390, `tiled January 23, 1961. The conduit 93 conveys the compressed air through an inter-cooler 94 and back to the inlet passage 95 in the second stage portion contained within the housing segment 13.

While a two stage compressor has been shown in the drawings, it will be understood that a single stage or more than two stages may be employed. Whether single or multiple stages are used, proper positioning of the housing segments with respect to the closure heads and divider wall or Walls is readily accomplished by turning the shaft 17 slowly before tightening the tension bolts 9. 'I'he spring-urged wiper bar contacts the cylindrical wall in each chamber and thus automatically centers the housing segments. The plane surfaces of 49 and 5t)I of the chamber `end Walls contact the parallel plane faces 96 and 97 of the housing segments, and the latter are free to slide upon them until the tension bolts are tightened to clamp t-he assembly together endwise.

Another advantageous feature resulting from the construction wherein plane surfaces on the closure heads and divider wall-s contact plane parallel faces on theA housing segments is that any desired number of stages may be assembled together by stacking standard component parts end to end.

Oil is admitted through restricted inlets 98 into each of the pressure cavities 34, and oil in larger quantities is admitted through lines '99 leading to the bearings 18 and 19. The oil from lthe lines 99 passes through the bearings and into lthe chambers within which the impellers are positioned. The oil lubricates the ends of the blades within the guide grooves 26, 27, 28 -and 29'. It passes from one end of each impeller to the other through the openings `52. The oil also passes axially through the recess 38 which holds the wiper bar assembly 36. The oil is carried out of the machine through 'the discharge passage 90 and through the discharge pipe 9'3. The oil is collected in the separator I101 and returned through pipe 102 to be used again. The air passing from the separator to the tank 82 carries very little entrained oil since substantially all of it is removed by the separator 101.

FIGURES 10, 11 and 13 show a modified form of the invention which employs rocker assemblies generally designated i for coordinating the reciprocating movement-s of the blades. This rocker assembly includes a rocker .111, arms y11-2 and springs 1,113 and `114-. This rocker assembly serves to coordinate the inward movement of one blade with the outward movement of the other. A matter to be considered is that the acceleration and deceleration exhibited in the downward movement of la blade as it is moved by the limpeller surface is not the equivalent of the simultaneous opposite movement of the other blade. Hence, at certain portions of the cycle of operation, there is a distinct and substantial phase difference in the relative position of two reciprocating blades and 116. Hence therefore, as a matter of geometry, a rigid rocker arm connecting the blades 115 and L16 cannot provide the solution desired. The rocker assembly y110 oscillates to absorb the greater proportion of the motion of the alternate displacement of the blades 1115 and :116 while 'the rollers 117 and their springs 113 and 114 afford suicient flexibility to overcome phase variations 'in the alternate lifting and lowering of the blades 115 and 1116.

' The size of the springs 11-3 and 114 are chosen with relation to the mass of the reciprocating parts and the operating speed of .the shaft in order to minimize impact between the wiper bar elements 118 and the blade rails 119. As best shown in FIGURE 13 the blade 115 and its rail 119 are capable of move-ment completely out of the chamber 121i to avoid interference with the wiper elements 118 on the periphery of the moving impeller 121. The leading and trailing edges 122 and 123 are rounded as shown and the outer surface l124 of the wiper bar elements which extend between the edges is substantially flat, rather than curved Ior crowned. As the impeller 121 turns the rail 1-19 is depressed to a greater and greater extent until it moves completely out of the path ont motion of the wiper bar elements 118 when the latter reaches the position of the slot l125. In other words the momentum of the blade 115 and rail 119" carries Ithese parts rto a retracted position to avoid any substantial impact with the Wiper bar elements. Each wiper bar assembly includes parallel bar elements 118 spread laterally within the impeller groove 19S, by means of a learf spring 109. .The wiper bar elements have sliding contact with the parallel end faces of the chamber 120.

Each of the blades 115 and 116 projects radially throughan axially extending radial slot 125 provided on one 'of the housing segments The side edges of the reciprocating blades 115 and 116 are guided in slots provided on walls of the housing. Each of the slots '125 is centrally enlarged by an axially extending bore 126 to receive sealing plugs or strips 127 and 128 which contact opposite faces of the blades. The plugs 127 and 128 are preferably formed of polytetrachloroethylene known to the trade as Teflon although metal or :synthetic rubber can be used. The outer lsurfaces of the plugs 127 and 128 comprise portions of cylinders so that the plugs are self aligning within the bore 126. The plug 127 has an upward pointed edge and the plug 128I has a downward pointing edge.

The general scheme of operation of this modified Iform of my invention is the same as'that previously described.

Having Afully described my invention it is to be understood that I do not wish to be limited :to the details set forth herein but my invention is of the full scope of the appended claims.

I claim:

1. In a fluid pump or the like, the combination of: two eccentric impellers lixed one-half revolution apart upon a rotary shaft, a housing rotatably supporting the shaft and provided with a cylindrical chamber for each eccentric impe-ller, each impeller having an element in wiping contact with a cylindrical wall of the chamber, a recipnocating blade `for each impeller slidably mounted upon the housing and each having a leading edge forming a seal with the outer surface of its respective impeller, the housing having a cavity into which the blades extend, a rocker within the cavity pivotally supported upon the housing, first and second arms pivotally mounted upon opposite ends of the rocker, a roller on each arm contacting one of said blades, and a spring interposed between each arm and said rocker, for resiliently urging each blade toward contact with its respective impeller.

2. In a fluid pump or the like, the combination of a stationary housing having a pair of aligned cylindrical chambers, a rotary shaft having a pair of cylindrical irn pellers diametrically loffset from the shaft axis, each irnpeller being positioned within one of said chambers and having an element thereof in wiping contact with an inner wall surface of its respective chamber, a pair of axially extending radially reciprocating blades slidably mounted on the housing in sideaby-side position, each blade having a leading edge engaging the outer surface of one of said impellers, a rocker pivotally mounted to oscillate on the housing, first and second arms pivotally mounted upon opposite ends of said rocker, means on each of said anms for contacting one of said blades, respectively, and resilient means carried on the rocker acting on each arm to move each of the blades radially inwardly in response to outward movement of the other, to maintain contact between :the blade edges and their respective impellers.

3. In a fluid pump or the like, the combination of: a stationary housing having a cylindrical chamber therein provided with parallel end surfaces, a rotary shaft having a cylindrical impeller thereon offset from the shaft axis and positioned within said chamber, an axially extending wiper bar mounted on said impeller and having wiping Contact with the inner cylindrical surface of said chamber and sliding contact with said end surfaces, said impeller having end faces confronting said parallel end surfaces of said chamber, said impeller end faces each having a radially and axially daring wall concentric with said impeller and intersecting said wiper bar, a split metal seal ring on each end yface resilienrtly engaging said flaring wall to expand into sealing contact with one of said chamber end surfaces, respectively, the ends of said metal seal ring straddling said wiper bar, the housing having an axial slot communicating with said chamber, and an axially extending radially reciprocating blade slidably mounted in said housing slot and contacting the cylindrical surface of said impeller.

4. The combination set forth in claim 3 in which the met-a1 seal rings are each provided with an outer tapered wall contacting one of said flaring walls on the irnpeller end faces.

5. The combination set forth in claim 3 in which radial guide grooves are provided in said parallel end faces for guiding the sides of said blade, and wherein said metal seal rings sweep over said radial guide grooves.

6. In a fluid pump or the like, the combination of: a stationary housing having means defining a plurality of aligned Icylindrical chambers, each chamber having parallel end surfaces, a rotary shaft having a plurality of eccentric cylindrical lmpellers thereon offset from the shaft axis, each impeller being positioned within one of said chambers, an axially extending wiper bar mounted on each impeller and having wiping contact with the inner cylindrical surface and sliding contact with said end surfaces of its respective chamber, each impeller having end faces confronting said parallel end surfaces of said chambers, each iinpeller end face having a radially and axially flaring wall concentric with said impeller and intersecting said Wiper bar, a split rnetal seal ring on each end face resiliently engaging said flaring Wall to expand into sealing contact with one of said chamber end surfaces, respectively, the ends of said metal seal ring straddling said wiper b-ar, the housing having a plurality of aligned axial slots, one extending from each chamber, and a plurality of axially extending radially reciprocating blades each slidably mounted in one of said housing slots, respective? ly, 'each blade contacting the cylindrical surface of one of said impellers.

7. ln a fluid pump or the like, the combination of: a stationary housing having a cylindrical chamber therein provided with parallel end surfaces, a rotary shaft having a cylindrical impeller thereon offset from the shaft axis and positioned within said chamber, an axially extending Wiper bar mounted on said impeller and having wiping contact with the inner cylindrical surface 'of said chamber and sliding contact with said end surfaces, said inn peller having end faces confronting said parallel end surfaces of said chamber, a split seal ring on each end face of said impeller, each split seal r-ing engaging one of said chamber end surfaces in sealing contact, each split seal rin-g having spaced apart ends which straddle said wiper bar, said wiper bar extending radially inward beyond the ends of said split seal rings, and an axially extending, radially reciprocating blade slidably mounted in said housing and lcontacting said impeller.

8. ln a fluid pump or fthe like, the combination of: a p

stationary housing having a cylindrical chamber therein provided with parallel end sui-faces, said parallel end faces having radial guide grooves, a rotary shaft having a cylindrical impeller thereon offset from the sha-ft axis and positioned within said chamber, an axially extending wiper bar mounted on said impeller and having wiping Contact with the inner cylindrical surface of said chamber and sliding contact with said end surfaces, said impeller having end faces conf-routing said parallel `end surfaces of said cham-ber, a split seal ring on each end face of said impeller, each split seal ning engaging one of said chamber end surfaces in sealing contact and sweeping over said radial guide grooves, each split seal ring having spaced apart ends which straddle said wiper bar, said wiper bar extending radially inward beyond the ends ofk said split seal rings, the housing having an axial slot communicating with said chamber, and an axially extending, radially reciprocating blade slidably mounted in said guide grooves and extending through said slot and contacting said impeller.

9. In a fluid pump or the like, the combination of: a stationary housing having a cylindrical chamber .therein provided with parallel end surfaces, a rotary shaft having a cylindrical impeller thereon offset from the shaft axis and positioned within said chamber, an axially ex-` tending =wiper bar mounted on said irnpeller and having wiping contact with the inner cylindrical surface of said chamber and sliding contact with said end surfaces, said impeller having end faces confronting said parallel end surfaces of said chamber, said impeller end faces each having a radially and axially flaring wall concentric with said impeller and intersecting said wiper bar, a spltmetal seal ring on each end face resiliently engaging said flaring wall to expand into sealing contact with one of said chamber end surfaces, each split seal ring having ends which straddle said wiper bar, and an axially extending, radially reciprocating blade slidably mounted in said housing and contacting said impeller.

l0. In a fluid pump or the like, having a cylindrical impeller mounted eccentrically to turn within a cylin-V drical chamber in a stationary housing and having a radial reciprocating blade contacting the impeller, the improvement comprising, in combination: parallel end surfaces on the housing defining end walls of the chamber, an axially extend-ing wiper bar mounted on the impeller and having wiping contact with the inner cylindrical surface of said chamber and sliding contact with said end surfaces, the impeller having end faces confronting said parallel cnd surfaces, a split seal ring on each end face of said impeller, each split seal ring engaging one of said chamber end surfaces in sealing contact, each split seal ring having spaced apart ends which straddle said wiper bar, and said wiper bar extending radially inward beyond the ends of said split seal rings.

ll. In a rotary fluid pump or the like, having a cylindrical impeller mounted eccentrically to turn within a cylindrical chamber in a stationary housing and having a radial reciprocating blade contacting the impeller, the improvement comprising, in combination: guide grooves on the housing engaged by said blade, a slot in the housing through which the reciprocating blade extends, the slot having an enlargement between the ends thereof, a pair of sealing plugs in said enlargement on opposite sides of the blade, the plugs each having a -frs-t portion shaped to conform to said enlargement and having a at portion contacting the blade, the hat portion intersecting said rst portion to form a pointed end on each sealing plug, each sealing plug also having a heel surface remote from its pointed end and exposing a portion of said enlargement, the pointed end of one of the sealing plugs lying adjacent said chamber and the pointed end of the other sealing plug being remote therefrom.

12. In a rotary fluid pump or the like, having a cylindrical impeller mounted eccentrically 4to turn within a cylindrical chamber in a stationary housing and having a radial reciprocating blade contacting the impeller, the improvement comprising, in combination: guide grooves on the housing engaged by said blade, a slot in the housing through Which the reciprocating blade extends, a cylindrical bore in the housing extending parallel to the axis of said cylindrical chamber and intersecting said slot to provide an enlargement thereof, a pair of sealing plugs in said bore on opposite sides of the blade, the plugs each having an arcuate portion shaped to conform to said bore, and having a flat portion for engagement with the blade, said arcuate portion intersecting said ilat portion to form a pointed end on each sealing plug, each sealing plug also having a heel surface remote from its pointed end and exposing a portion of said enlargement, the pointed end of one of the sealing plugs lying adjacent said chamber and lthe pointed end of the other sealing plug being remote therefrom.

13. In a rotary uid pump or the like, having la cylindrical impeller mounted eccentrically rtoturn Within a cylindrical chamber in a stationary housing and having a radial reciprocating blade contacting the impeller, the improvement comprising, in combination: guide grooves on the housing engaged by said blade, a slot in the housing through which the reciprocating blade extends, the slot having an enlargement between the ends thereof, a pair of metal sealing plugs in said enlargement on opposite sides of the blade, the plugs each having a first portion shaped to conform to said enlargement and having a flat portion contacting the blade, the flat portion intersecting said rst portion to form a pointed end on each sealing plug, each sealing plug also having a blunt end remote from its pointed end, the pointed ends of said sealing plugs being oppositely directed, and Ia resilient element on said rst portion of each sealing plug contacting said enlargement.

14. `In a rotary fluid pump or the like, having a cylind rical impeller mounted eccentn'cally to turn Within a cylindrical chamber in a stationary housing and having a radial reciprocating blade contacting the impeller, the improvement comprising, in combination: guide grooves on the housing engaged by said blade, a slot in the housing through which the reciprocating blade extends, a cylindrical bore in the housing extending parallel to the axis of said cylindrical chamber and intersecting said slot to provide an enlargement thereof, a pair of substantially duplicate sealing plugs in the bore on opposite sides of the blade, the plugs each having an arcuate portion shaped to conform to said bore, and having a flat portion for engagement with the blade, said arcuate portion intersecting said flat portion to formi a pointed end on each sealing plug, each sealing remote from said pointed end exposing a portion of said bore, the pointed end of one of the sealing plugs lying adjacent said chamber and the pointed end of the other plug also having a heel surface v l@ sealing plug being remote therefrom, the clearances and proportions of the blade, bore, and sealing plugs being such that the sealing plugs reciprocate in the bore in the direction of travel of the blade.

15. In a rotary fluid pump or the like, having a cyl-indrioal impeller mounted eccentrically to turn within a cylindrical chamber in a stationary housing and having a radial reciprocating metal blade contacting the impeller, the improvement comprising in combination: guide grooves on the housing engaged by said blade, a cavity in the housing, a slot inthe housing connecting the cavity to the chamber, the reciprocating blade extending through :the slot, a bore in the housing extending parallel to the `axis of said cylindrical chamber and intersecting said slot to provide lan enlargement thereof, a pair of metal sealing plugs in the bore contacting opposite sides of the blade, the plugs each haiving `a irst por-tion shaped to conform to said bore, Vand having a fiat portion for engagement with the blade, said first portion intersecting said at portion to form a pointed end on each sealing plug, each sealing plug also having la blunt end 4remote [from said pointed end and out of contact with said bore, the pointed ends of the sealing plugs being oppositely directed so that one of them faces said cavity and the other haces said chamber, resilient elements extending along the length of said plugs engaging the bore between the pointed end and the blunt end of each sealing plug, the sealing plugs being suiiiciently loose in said bore to permit them to move with the reciprocating blade for a short distance at each end of the stroke of the blade.

16. In a rotary fluid pump or the like, having a cylindrical impeller mounted eccentrically to turn within a cylindrical chamber in a stationary housing and having a radial reciprocating blade contacting the impeller, the improvement comprising, in combination: a slot fin the housing through which the reciprocating blade extends, the slot having an enlargement between the ends thereof, a pair of Teflon sealing plugs in said enlargement on opposite sides of the blade, the plugs each having a first portion shaped to conform to said enlargement and having a flat portion contacting the blade, the flat portion intersecting said irst portion to form a pointed end on each sealing plug, each sealing plug also having a heel surface remote from its pointed end and exposing a portion of said enlargement, the pointed end of one of the sealing plugs lying adjacent said chamber and the pointed end of the other sealing plug being remote therefrom.

17. In a fluid pump or the like, the combination of: a stationary housing having a cylindrical chamber, a rotary shaft having an eccentric cylindrical impeller thereon offset from the shaft axis, said impeller being positioncd Within said chamber, an axially extending wiper bar assembly mounted on said impeller and having wiping contact with the inner cylindrical surface of said chamber, the housing having a cavity and an axial slot connecting said chamber to said cavity, an axially extending radially reciprocating blade extending through Isaid housing slot and contacting the cylindrical surface of said impeller, seal means in said slot engaging said blade, and a motionreversing device in said cavity adapted to contact and apply a reversing force to said reciprocating blade only after it has completed part of its outward stroke.

18. ln a fluid pump or the like, the combination of: a stationary housing having means defining a plurality of aligned cylindrical chambers, a rotary shaft having a plurality of eccentric impellers thereon offset from the shaft axis, each impeller being positioned within one of said chambers, an axially extending wiper bar assembly mounted on each impeller and having wiping contact with the inner cylindrical surface of its respective chamber, the housing having a separate cavity for each of said chambers, the housing also having plurality of axial slots each connecting one of said chambers to its respective cavity, a plurality of axially extending radially reciprocating blades each extending through one of said'housing slots,

li i

respectively, seal means in said slots engaging said blades, each blade contacting the cylindrical surface of one of said irnpellers, bias means for applying a force toeach blade in its cavity to maintain it in contact with its respective impeller, and a motion-reversing device in each of said cavities and each adapted to contact and apply a reversing force to said reciprocating blade only after it has completed part of its outward stroke.

19. In a duid pump or the like, the combination of: a stationary housing having a cylindrical chamber, a rotary shaft having an eccentric cylindrical impeller thereon offset from the shaft axis, said impeller being positioned within said chamber, an axially extending wiper bar assembly mounted on said impeller and having wiping contact with the inner cylindrical surface of said chamber, the housing having a cavity and an axial slot connecting said charnber to said cavity, an axially extending radially reciprocating blade extending through said housing slot and contacting the cylindrical surface of said impeller, seal means in said slot engaging said blade, and a motion-reversing device in said cavity including a movable element adapted to contact and apply a reversing force to said reciprocating blade only after it has completed part of its outward stroke, and bias means acting to move said element toward said blade.

20. In a fluid pump or the like, the combination of: a stationary housing having a cylindrical chamber, a rotary shaft having an eccentric cylindrical impeller thereon offset from the shaft axis, said irnpeller being positioned within said chamber, an axially extending wiper bar assembly mounted on said impeller and having wiping contact with the inner cylindrical surface of said chamber, the housing having a pressure cavity and an axial slot connecting said chamber to said pressure cavity, an axially extending radially reciprocating blade extending through said housing slot and contacting the cylindrical surface of said impeller, seal means in said slot engaging said blade, a motion-reversing device in said pressure cavity adapted to contact and apply a reversing force to said reciprocating blade only after it has completed part of its outward stroke, and means for pressurizing said cavity.

2l. In a multiple stage rotary fluid pump or the like, the combination of: a stationary housing having means defining a plurality of aligned cylindrical chambers, one for each stage, a rotary shaft having a plurality of eccentric cylindrical impellers thereon offset from the shaft axis, each impeller being positioned within one of said chambers, an axially extending wiper bar assembly mounted on each impeller and having wiping contact with the inner cylindrical surface of its respective chamber, the housing having a separate pressure cavity for each of said chambers, the housing also having plurality of aligned axial slots each connecting one of said chambers to its respective cavity, a plurality of axially extending radially reciprocating blades, each extending through one of said housing slots, respectively, seal means in said slots engaging said blades, each blade contacting the cylindrical surface of one of said impellers, and means for pressurizing one of said pressure cavities from a chamber associated with another pressure cavity.

22. In a fluid pump or the like, the combination of: a stationary housing having a cylindrical chamber, a rotary shaft having an eccentric cylindrical impeller thereon offset from the shaft axis, said irnpeller being positioned within said chamber and having a wiper bar in contact with the inner cylindrical surface of said chamber, the housing having a pressure cavity and an axial slot connecting said chamber to said pressure cavity, an axially extending radially reciprocating blade extending through said housing slot and contacting the cylindrical surface of said impeller, seal means in said slot engaging said blade, a motion-reversing device in said pressure cavity adapted to contact and apply a reversing force to said reciprocating blade only after it has completed part of its outward stroke, means on the housing for admitting a lubricant into said pressure cavity, and means on the housing for introducing a gas under pressure into said pressure cavity for maintaining said blade in contact with said impeller.

23. In a multiple stage rotary fluid pump or the like, the combination of: a plurality of stationary housing sections each having a cylindrical bore extending between parallel side faces of the housing sections, at least one divider plate interposed between two of said housing sections and having parallel walls slidably contacting sidefaces of said housing sections, a pair of closure heads each having an end surface slidably contacting a side face of one of said housing sections, a rotary shaft having a plurality of eccentric cylindrical impellers xed thereon offset from the shaft axis, each impeller being positioned within one of said housing sections, each impeller having an axially extending element in wiping Contact with the cylindrical bore of its respective housing section, bearing means on said closure heads for rotatably supporting said shaft, seal means on said divider plate engaging said shaft, each housing section having an axial slot, a plurality of axially extending radially reciprocating blades, one in each housing slot, each blade contacting one of said impellers, the end surfaces of the closure heads and the side walls of the divider plate having radially extending guide slots receiving side edges of said blades, whereby alignment of the housing sections with respect to the closure heads and divider plate may be achieved by turning of the rotary shaft, and means for securing the housing sections, closure heads and divider plate in aligned position.

24. ln a two stage rotary uid pump or the like, the

combination of: a pair of stationary housing sections each having a cylindrical bore extending between parallel side faces of the housing section, a divider plate interposed between the two housing sections and having parallel walls slidably contacting side faces of said housing sections, a pair of closure heads each having an end surface slidably contacting a side face of one of said housing sections, a rotary shaft having a pair of eccentric cylindricalVV impellers xed thereon offset from the shaft axis, each impeller being positioned within one of said housing sections, each impeller having an axially extending element in wiping contact with the cylindrical bore of its respecl tive housing section, bearing means on said closure heads for rotatably supporting said shaft, seal means on said divider plate engaging said shaft, each housing section having an axial slot, a plurality of axially extending radially reciprocating blades, one in each housing slot, each blade contacting one of said impellers, the end surfaces of the closure heads and the side walls Vof the divider plate having radially extending guide slots receiving side edges of said blades, whereby alignment of the housing sections with respect to the closure heads and divider plate may be achieved by turning of the rotary shaft, and means for securing the housing sections, closure heads and divider plate in aligned position.

25. In a huid pump or the like, the combination of: a stationary housing having a cylindrical chamber therein provided with parallel end surfaces, a rotary shaft having a cylindrical impeller thereon offset from the shaft axis and positioned within said chamber, bearing means on said housing for rotatably supporting said shaft, an axially extending wiper bar mounted on said impeller and having wiping contact with the inner cylindrical surface of said chamber and sliding contact with said end surfaces, said impeller having end faces confronting said parallel end surfaces of said chamber, a split seal ring on each end face of said impeller, each split seal ring engaging one of said chamber end surfaces in sealing contact, each split seal ring having spaced apart ends which straddle said wiper bar, means for introducing a lubricant through said bearing means and into the space between the confronting end faces of the impeller and the end surfaces of the chamber, and an axially extending, radially reciprocating blade slidably mounted in said housing and contacting saidV impeller.

26. In a fluid pump or the like, the combination of: a stationary housing having a cylindrical chamber therein provided with parallel end surfaces, a rotary shaft having a cylindrical impeller thereon offset from the shaft axis and positioned within said chamber, an axially extending wiper bar mounted on said impeller and having wiping contact with the inner cylindrical surface of said chamber and sliding contact with said end surfaces, said impeller having end faces confronting said parallel end surfaces of said chamber, said impeller end faces each having a radially and axially flaring wall concentric with said impeller and intersecting said wiper bar, a split metal seal ring on each end face resiliently engaging said aring wall to expand into sealing contact with one of said chamber end surfaces, respectively, the ends of said metal seal ring straddling said wiper bar, means for introducing a lubricant into the space between the confronting end faces of the impeller and the end surfaces of the chamber and radially within said flaring wall, the housing having an axial slot communicating with said chamber, and an axially extending radially reciprocating blade slidably mounted in said housing slot and contacting the cylindrical surface of said impeller.

27. In a fluid pump or the like, the combination of: a stationary housing having a cylindrical chamber therein provided with parallel end surfaces, a rotary shaft having a cylindrical impeller thereon offset from the shaft axis and positioned within said chamber, an axially extending Wiper bar mounted on said impeller and having wiping contact with the inner cylindrical surface of said chamber and sliding contact with said end surfaces, said impeller having end faces confronting said parallel end surfaces of i ai Y said chamber, said impeller end faces each having a radially and axially flaring wall concentric with said impeller and intersecting said wiper bar, said flaring wall being positioned adjacent the outer surface of the cylindrical impeller, a split metal seal ring on each end face resiliently engaging said Haring wall to expand into sealing contact with one of said chamber end surfaces, respectively, the ends of said metal seal ring straddling said wiper bar, the housing having an axial slot communicating with said chamber, and an axially extending radially reciprocating blade slidably mounted in said housing slot and contacting the cylindrical surface of said impeller.

References Cited in the file of this patent UNITED STATES PATENTS Re. 24,975 Wallimann Apr. 25, 1961 273,446 Blake Mar. 16, 1883 518,635 Tasker Apr. 24, 1894 669,461 Kochendarfer et al Mar. 5, 1901 902,762 Risley Nov. 3, 1908 936,932 Neumann Oct. 12, 1909 985,562 Williams Feb. 28, 1911 1,049,615 Sleigh Jan. 7, 1913 1,391,324 Keith Sept. 20, 1921 1,827,088 Jaworowski Oct. 13, 1931 FOREIGN PATENTS 26,729 Switzerland of 1902 219,650 Great Britain Feb. 12, 1925 

1. IN A FLUID PUMP OR THE LIKE, THE COMBINATION OF: TWO ECCENTRIC IMPELLERS FIXED ONE-HALF REVOLUTION APART UPON A ROTARY SHAFT, A HOUSING ROTATABLY SUPPORTING THE SHAFT AND PROVIDED WITH A CYLINDRICAL CHAMBER FOR EACH ECCENTRIC IMPELLER, EACH IMPELLER HAVING AN ELEMENT IN WIPING CONTACT WITH A CYLINDRICAL WALL OF THE CHAMBER, A RECIPROCATING BLADE FOR EACH IMPELLER SLIDABLY MOUNTED UPON THE HOUSING AND EACH HAVING A LEADING EDGE FORMING A SEAL WITH THE OUTER SURFACE OF ITS RESPECTIVE IMPELLER, THE HOUSING HAVING A CAVITY INTO WHICH THE BLADES EXTEND, A ROCKER WITHIN THE CAVITY PIVOTALLY SUPPORTED UPON THE HOUSING, FIRST AND SECOND ARMS PIVOTALLY MOUNTED UPON OPPOSITE ENDS OF THE ROCKER, A ROLLER ON EACH ARM CONTACTING ONE OF SAID BLADES, AND A SPRING INTERPOSED BETWEEN EACH ARM AND SAID ROCKER, FOR RESILIENTLY URGING EACH BLADE TOWARD CONTACT WITH ITS RESPECTIVE IMPELLER. 